There have been proposed various gas-adsorbing devices in order to be used in an evacuated insulating body that is manufactured by covering a core with a jacket having gas barrier properties and reducing pressure inside the jacket. The gas-adsorbing devices contain a gas adsorptive substance capable of adsorbing an air component, particularly, nitrogen as an adsorption-resistive gas.
Such gas-adsorbing devices adsorb a gas, which is not completely removed by an industrial evacuation process, but remains inside the jacket of an insulating body, and remove the gas from the inside of the jacket such that a heat insulation capacity is improved. However, when the gas-adsorbing device is brought into contact with air before being applied to the insulating body, the gas adsorptive substance of the gas-adsorbing device adsorbs an air component or the like and a part of the substance is likely to be consumed.
For example, there has been proposed a device in order to maintain a vacuum in an insulated jacket. In the device, an open-top container formed of a gas-impermeable material is filled with a Ba—Li alloy having reactivity to a gas such as nitrogen even at room temperature. Powder of a dry material is disposed in the top portion of the container so as to cover the Ba—Li alloy (for example, see PTL 1).
In the device, the powder of the dry material is disposed, thereby making it possible to reduce moisture adsorption by the Ba—Li alloy and thus, making it possible to reduce consumption of the Ba—Li alloy due to the moisture adsorption.
In addition, there has been proposed a container that contains a gas adsorbent in order to be used in an evacuated insulating material. The container includes an outer shell that covers the gas adsorbent, and a communicating portion through which the inside and the outside of the outer shell communicate with each other when a predetermined external force is applied, but the inside and the outside of the outer shell do not communicate with each other when no external force is applied (for example, see PTL 2).
In the container in which the gas adsorbent is contained, the outer shell prevents the gas adsorbent from being exposed to air or the like, and, when the gas adsorbent is used, an external force applied to the communicating portion causes the inside and the outside of the outer shell to communicate with each other such that gas adsorption is started. Hence, according to the container, it is possible to reduce consumption of the gas adsorbent and thus, it is possible to maintain a high adsorption performance in any environment.
In addition, there has been also proposed a gas-adsorbing device using a gas-permeability resistive container having one end opened and the other end sealed. The gas-permeability resistive container is formed of a hollow cylindrical metal member having a body portion of which a length from one end to the other end is equal to or longer than the maximum width of an end portion. When the gas-adsorbing device is manufactured, the gas-permeability resistive container is filled with the gas adsorbent from an opening, and then, a sealing member is disposed in the vicinity of the opening inside the opening. Then, the sealing member is heated and melted, and then, the sealing member inside the opening is cooled and is solidified, thereby sealing the opening (for example, see PTL 3).
Use of the device makes it possible to reduce degradation of the gas adsorbent during the process of disposing the gas-adsorbing device in a space having air as an adsorption target. Further, in the gas-adsorbing device, at least one of the sealing member, an interface between the sealing member and the gas-permeability resistive container, or the gas-permeability resistive container, is broken such that the inside and the outside of the gas-permeability resistive container communicate with each other. Thus, the gas-adsorbing device can adsorb a gas as the adsorption target.
Here, the gas adsorbent containing copper ion-exchanged ZSM-5-type zeolite is characterized by a higher gas adsorption capacity and a higher adsorption rate than a gas adsorbent in the related art. On the other hand, similar to the gas adsorbent in the related art, when the gas adsorbent is brought into contact with air before being applied to a space having a gas as the adsorption target, such as the insulating body, the gas adsorbent adsorbs nitrogen, oxygen, moisture, and the like and is consumed. Then, this results in reduction of the capacity of adsorbing air which is not completely removed by the industrial evacuation process, but remains in the inside of the jacket of the evacuated insulating body.
In the device disclosed in PTL 1, the Ba—Li alloy has a relatively low capacity of nitrogen adsorption and a slow adsorption rate. In addition, Ba is a substance designated by the Pollutant Release and Transfer Register (PRTR) at least in Japan. Therefore, it is desirable that, when a material containing Ba is industrially used, the material is safe for the environment and humans. In addition, the covering with the powder of the dry material can reduce an amount of moisture reaching the Ba—Li alloy; however, it is not possible to prevent the air from reaching the alloy. Therefore, the Ba—Li alloy is likely to adsorb the air and a part thereof is likely to be consumed.
In addition, in technology disclosed in PTL 2, control of non-communication or communication between the inside and the outside of the container containing the gas adsorbent is performed by the external force. Thus, it is possible to prevent consumption of the gas adsorbent by the communication between the inside and the outside of the container in the inside of the insulator at a required timing. On the other hand, the external force is required for the control and thus, there are costs required for applying a mechanism to the container. Further, in the case where moisture is contained in the gas, which is not completely removed by the industrial evacuation process, but remains inside the jacket, it is not possible to reduce consumption of the gas adsorbent due to the moisture adsorption.
In addition, in the device disclosed in PTL 3, when the gas as the adsorption target is adsorbed, the device is disposed in a space having the gas and then, there is a need to apply a force from the outside of the space so as to break the sealing member.